大気へのガス経路としての北極の湖や川: ツンドラの炭素予算への影響
まとめ
北極のツンドラの水生生態系は,大気中に二酸化炭素 (CO2) を放出し,純粋に陸上の炭素吸収の仮定に異議を唱える. この発見は,現在の炭素シンクの推定値が過大評価されている可能性があることを示唆しています.
科学分野:
- 環境科学 環境科学
- エコロジー エコロジー エコロジー
- 気候科学 気候科学
背景:
- 北極のツンドラは,かなりの量の炭素を貯蔵しており,大気中の二酸化炭素 (CO2) のシンクと考えられています.
- 以前の炭素バランスの見積もりは,陸上の生態系のみに焦点を当て,水中の貢献を潜在的に見過ごしていた.
研究 の 目的:
- 北極やアラスカの水生生態系における二酸化炭素 (CO2) 流れを調査する.
- 北極の全体的な炭素予算における水生システムの役割を評価する.
主な方法:
- 29の多様な水生生態系における二酸化炭素 (CO2) の部分圧力測定.
- 表面水から大気中に排出されるCO2の分析.
主要な成果:
- 29の水生生態系のうち27の生態系が,CO2を大気中に排出する純排出量を示した.
- 水系から放出される二酸化炭素は,侵食や地下水輸送を通じて,陸上ツンドラ環境から発生している可能性が高い.
- この水中のCO2フロースは,北極の陸上の炭素シンクの現在の推定値が最大20%まで過大評価されている可能性があることを示唆しています.
結論:
- 北極の水生生態系は,大気中のCO2の重要な源であり,シンクではない.
- 北極のツンドラにおける陸上の炭素吸収量の推定は,水域システムからの貢献を含めるように改定する必要があります.
- 北極の炭素循環を完全に理解するには,陸上と水上の両方の流れを考慮する必要があります.
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